JP5921515B2 - Process for producing processed cooked rice - Google Patents

Description

The present invention relates to a method for producing processed cooked rice with good looseness. More specifically, the present invention relates to a method for producing processed cooked rice that improves the loosening of cooked rice by adding two or more amylases having different optimum working temperatures to the cooked rice process, and has an excellent texture. Furthermore, it is related with the processed cooked rice manufactured by the manufacturing method of this invention.

  With recent diversification of food and Westernization, Japanese rice consumption has been decreasing year by year. Therefore, there is a strong demand for the development of processed rice foods for expanding rice consumption, such as dry cooked rice (Patent Document 1) and frozen food (Patent Document 2) used for instant foods (boiled rice, miscellaneous cooking, risotto, etc.). Is provided.

  In particular, dry rice used for instant foods is strongly required to improve its resilience, and in order to shorten the restoration time of dry rice and improve its resilience, alpha rice and expanded rice are processed for instant food. The method of using it is also researched and developed (patent documents 3 to 5). Here, the pregelatinized rice is a product obtained by rapidly drying water to 17% or less in a state where the starch is pregelatinized after cooking rice so that the structure of the polished rice is not broken. Thereby, starch can be hold | maintained for a long time with an alpha-ized state, and it can restore | restore to a state like cooked rice normally within several tens of minutes only by adding water or hot water. In addition, the expanded dry rice is dry rice obtained by adjusting the moisture after the rice has been gelatinized (after cooking or steaming) and then expanding the tissue by increasing the drying temperature thereafter. Such puffed and dried rice is restored so that it can be eaten when hot water is poured and held for several minutes, or it is restored so that it can be eaten by adding water and cooking in a microwave oven.

  Currently, the dried rice that is generally used is produced by cooking hot rice or vacuum freeze-drying the cooked rice obtained by conventional methods, but in the production process, the rice is loosened, weighed, filled, It is necessary to mechanize processes such as molding, and improvement of cooked rice is required, such as reduction of adhesion between rice grains and adhesion to machines in these processes.

  Also, the stickiness and hardness of cooked rice are very important factors for the taste. In the case of white rice and many processed rice, when the water content after cooking decreases, the loosening of the cooked rice tends to improve, but the cooked rice has a hard texture lacking in stickiness. On the other hand, when the water content after cooking is high, cooked rice with moderate stickiness and hardness can be obtained, but the looseness of the cooked rice tends to be poor, resulting in uneven drying and uneven texture. For this reason, development of the manufacturing method of the processed cooked rice which made the loosening of cooked rice in the case where the water | moisture content after cooking rice is high, and the improvement of texture have been desired.

  There is an example in which an enzyme composition for cooking rice containing a heat-resistant α-amylase has been developed to improve the loosening of cooked rice, but (Patent Document 6), the effect is not sufficiently satisfactory, A more effective method has been demanded.

JP-A-9-294554 JP-A-11-285352 JP 7-31389 A JP-A-51-32751 JP 51-121542 A Japanese Patent Laid-Open No. 7-289186

In order to improve the looseness of cooked rice, in addition to using an enzyme composition for cooking rice containing heat-resistant α-amylase during cooking, various emulsifiers and fats and oils can be added, or a special rice cooking machine The method of using was taken. However, these methods have major problems in taste changes, rice damage, and the like, and are not a production method that achieves both loosening of rice and improving the texture.
An object of the present invention is to provide a production method for producing processed cooked rice, in which the cooked rice is easily loosened, has a good texture, and has little variation in texture. Moreover, it is providing the processed cooked rice manufactured by the manufacturing method of this invention.

  This inventor repeated earnest research about the rice cooking method in process cooked rice manufacture, and earnestly examined the method of cooking the cooked rice with good unraveled rice and excellent texture. As a result, surprisingly, it was found that these problems were solved by the rice cooking process using two or more kinds of amylases having different optimum working temperatures, and extremely excellent cooked cooked rice could be produced. Was completed.

  Furthermore, this invention is a manufacturing method of processed cooked rice whose 1 or more types of amylase is a thermostable amylase among the said amylases.

  More specifically, it is a method for producing processed cooked rice using one or more amylases having an optimum amylase temperature of 60 to 100 ° C. and one or more amylases having a temperature of 30 to 60 ° C. The optimum temperature for action in the present invention refers to the peak temperature at which the action effect of the enzyme is highest.

  Moreover, it is a manufacturing method of the processed cooked rice whose 1 or more types of amylase is alpha-amylase among the said amylases.

  Further, the processed cooked rice is a method for producing processed cooked rice using amylase in the form of pregelatinized rice, expanded dried rice, vacuum freeze dried rice, chilled cooked rice, or frozen cooked rice.

  Moreover, the processed cooked rice concerning this invention is manufactured by the manufacturing method of the said cooked cooked rice, and is a cooked cooked rice with the good loosening of cooked rice, and excellent food texture.

In the production method of the present invention, in the production of processed cooked rice, the looseness of cooked rice is good, and as a result, it is possible to produce a cooked cooked rice excellent in quality with little variation in texture during eating.
Furthermore, the production method of the present invention is useful for improving the yield in cooked rice processing because of good loosening of cooked rice, and reducing drying unevenness when a drying process is involved, and contributing to stabilization of the process and quality. Technology.
In addition, the processed cooked rice of the present invention is a cooked cooked rice that is produced as described above and has a good looseness and texture of cooked rice.

Embodiments of the present invention will be described below. The present invention is not limited to the following description.

  The raw material rice used in the present invention is not particularly limited, such as japonica, indica, long grain, and short grain rice, and various kinds of rice can be used. Furthermore, old rice can also be used effectively.

Moreover, the amylase used by this invention can select and use 2 or more types from which the optimal temperature of action differs. As the amylase used in the present invention, α-amylase, β-amylase, glucoamylase, isoamylase and the like can be used, and for each enzyme, a heat-resistant enzyme or a non-heat-resistant enzyme can be arbitrarily selected. . Preferably, one or more types of thermostable amylase and non-thermostable amylase are selected. For example, one or more thermostable amylases having an optimum temperature of action of 60 to 100 ° C. and one or more non-thermostable amylases having an optimum temperature of action of 30 to 60 ° C. may be selected. Furthermore, when the heat-resistant amylase and the non-heat-resistant amylase are respectively used as the heat-resistant α-amylase and the non-heat-resistant α-amylase, extremely excellent effects can be obtained for the unraveling of rice and improving the texture. That is, if amylases having different optimum temperatures are used in combination, the textured rice has little variation during eating, and excellent processed cooked rice can be produced.
Hereinafter, unless otherwise specified, the non-thermostable α-amylase is simply referred to as α-amylase.

  As the thermostable α-amylase, for example, a thermostable α-amylase derived from Bacillus can be used. As the α-amylase, for example, α-amylase derived from Aspergillus or Bacillus can be used. More specifically, examples of the thermostable α-amylase include Christase (registered trademark) E5CC (manufactured by Amano Enzyme) having an optimum temperature of action of 70 ° C., and the α-amylase includes Biozyme (registered trademark) A (manufactured by Amano Enzyme) having an optimum action temperature of 55 ° C. can be mentioned.

  The amount of amylase used in the present invention is appropriately determined so as to obtain the intended effect, but for each amylase, it is usually 0.01 to 20 U, preferably 0.1 to 10 U, per 1 g of rice.

  Moreover, the amylase in this invention can be added before cooking rice during cooking rice in a rice cooking process, For example, what is necessary is just to add amylase to the water added at a rice cooking process.

  In the present invention, oils, emulsifiers, polymerized phosphates, and antioxidants can be used as auxiliary materials within a range that does not adversely affect the taste and the like. In addition, seasonings such as salt, soy sauce and sugar may be used for seasoning.

  Although the rice cooking method in this invention is not restrict | limited in particular, What is necessary is just to cook rice by normal methods, such as gas type rice cooking, electric rice cooking, IH type rice cooking, and rice cooking by steaming. Moreover, what is necessary is just to adjust the amount of water as needed and to cook rice so that the cooked rice of the texture which has the desired stickiness and hardness after cooking can be obtained. For example, rice can be cooked by adjusting the amount of water as appropriate so that the rice cooking yield is 1.6 to 2.6 (corresponding to 49 to 68% in terms of moisture after cooking). Here, rice cooking yield is the weight ratio of rice after cooking to the weight of rice before cooking.

  In general, in order to obtain cooked rice having moderate stickiness and hardness, it is said that the cooked rice yield should be about 1.8 to 2.4 (corresponding to 53 to 63% by boiling water). As rice cooking yield increases, the loosening of cooked rice tends to worsen. On the other hand, the cooked rice cooked according to the present invention has a good looseness of cooked rice compared to cooked rice with the same cooked rice yield without using amylase.

  In the production of processed cooked rice, the ease of unraveling of cooked rice during processing can reduce drying unevenness, stabilize freezing, and improve yield when a drying process or freezing process is performed after cooking. Processed cooked rice can be produced. In this case, known methods can be applied to the drying method and the freezing method.

  Processed cooked rice produced by the production method of the present invention includes ordinary white rice, brown rice, red rice, rice cake, cooked rice, curry rice, hayashi rice, cooked cooked rice with oysters and seasonings, and these pregelatinized rice and swollen rice Dry rice, dried rice such as vacuum freeze-dried rice, chilled rice, frozen rice, etc.

  Hereinafter, a comparative experiment will be described as an example.

  About the amylase used in the Example and the comparative example, the kind and optimal temperature of action are shown in Table 1. Hereinafter, in Examples and Comparative Examples, the enzyme Nos. Shown in Table 1 were used. To explain.

Example 1
After washing and draining 700 g of polished white rice, Enzyme 1 is 90 U / kettle, Enzyme 2 is 90 U / kettle, Salt is 1 g / kg, Emulsified oil and fat is 8.25 g / kg, Sucrose fatty acid ester is 3 g / kg, Polymerized phosphate was uniformly mixed at 1.8 g / kg. This is cooked for 15 minutes with a rice cooker (Rinnai gas rice cooker RR-10KS) at a water content of 160% of the rice weight, and steamed for 20 minutes, resulting in a rice cooking yield of 2.37 (63% water after cooking). Cooked rice, which is equivalent to%). This was loosened while blowing air.
The loosely cooked cooked rice was primarily dried at a temperature of 70 ° C. in a drying cabinet and a wind speed of 1 m / s for 35 minutes until the water content reached 26% (weight ratio). After leaving for about 30 minutes after the primary drying, it was sieved to remove anything that was severely bound, and it was pressed between two rolls with a first roll interval of 0.35 mm and a second roll interval of 0.35 mm. .
The pressed rice that had been crushed was secondarily dried to a moisture content of 16% at an internal temperature of 70 ° C. and a wind speed of 1 m / s for 15 minutes. After being left for about 30 minutes after the secondary drying, it was swelled and dried for 60 seconds at 150 ° C. and a wind speed of 55 m / s with a high-temperature high-speed air dryer capable of jetting a high-temperature air current at high speed. By this expansion drying, the dried rice was expanded to obtain expanded dried rice having a water content of 8%.

(Example 2)
Manufactured in the same manner as in Example 1 except that the amount of enzyme used in Example 1 was 90 U / kettle for enzyme 1 and 90 U / kettle for enzyme 3 to obtain swollen dried rice.

(Example 3)
Production was carried out in the same manner as in Example 1 except that the amount of enzyme used in Example 1 was 90 U / kettle for enzyme 1 and 90 U / kettle for enzyme 4 to obtain swollen dried rice.

(Comparative Example 1)
Production was carried out in the same manner as in Example 1 except that the enzyme was not used in Example 1, and swollen and dried rice was obtained.

(Comparative Example 2)
Production was carried out in the same manner as in Example 1 except that only the enzyme 1 was used as the enzyme used in Example 1 and the amount added was 90 U / pot, and swollen dried rice was obtained.

(Comparative Example 3)
Production was carried out in the same manner as in Example 1 except that only the enzyme 2 was used as the enzyme used in Example 1 and the amount added was 90 U / kettle to obtain expanded dried rice.

(Comparative Example 4)
Production was carried out in the same manner as in Example 1 except that only the enzyme 3 was used as the enzyme used in Example 1 and the amount added was 90 U / pot, and swollen dried rice was obtained.

(Comparative Example 5)
Production was carried out in the same manner as in Example 1 except that only the enzyme 4 was used as the enzyme used in Example 1 and the amount added was 90 U / pot, and swollen dried rice was obtained.

(Comparative Example 6)
Production was carried out in the same manner as in Example 1 except that only the enzyme 1 was used as the enzyme used in Example 1 and the amount added was 180 U / pot.

About the cooked rice after the primary drying in Examples 1 to 3 and Comparative Examples 1 to 6, through a 3.5 mesh sieve, weighed each divided into what passed through the sieve and what remained on the sieve, The binding rate was calculated by the following formula, and the loosening of cooked rice during drying was evaluated. Evaluation was made into 5 step | paragraph evaluation and the comparative example 1 was performed as "2" which hits the 2nd from the bottom.
Binding rate (%) = (weight of cooked rice remaining on the sieve) / (total weight of cooked rice) × 100

  The swollen and dried rice obtained in Examples 1 to 3 and Comparative Examples 1 to 6 is put in a cup-shaped plastic container, 37.5 g of powdered curry soup, 2.5 g of dried beef, 1.5 g of dried potatoes, dried Carrot 0.5g was added and mixed, 260ml of water at 25 ° C was added and stirred gently, then covered, cooked in a microwave oven 500W for 5 minutes 30 seconds, taken out of the microwave oven to make an instant curry rice . This was eaten by five skilled panelists, and the texture of the cooked rice after restoration was evaluated. Evaluation was made into 5 step | paragraph evaluation and the comparative example 1 was performed as "2" which hits the 2nd from the bottom.

  Table 2 shows the binding rates of Examples 1 to 3 and Comparative Examples 1 to 6, loosening of cooked rice, and sensory evaluation results.

First, only one type of amylase was used, and the effect of the type of amylase on the unraveling of rice and improvement in texture was examined (Comparative Examples 1 to 5).
As shown in Table 2, when the heat-resistant α-amylase was used in the rice cooking process (Comparative Example 2), the binding rate decreased compared to the case where the enzyme was not used (Comparative Example 1), and the rice was loosened. Was confirmed to be improved. Regarding the texture, it was confirmed that, compared with Comparative Example 1, the texture was improved and improved. Moreover, when (alpha) -amylase is used for a rice cooking process (comparative examples 3 and 4), although improvement was not seen about the loosening of cooked rice, it becomes favorable food texture in which the restoring property was improved. It was confirmed. In addition, when glucoamylase was used in the rice cooking process (Comparative Example 5), neither the loosening of the cooked rice nor the texture was affected.
Furthermore, the heat-stable α-amylase, which was confirmed to have an improved effect on the looseness and texture of cooked rice, was examined by increasing the amount of enzyme used (Comparative Example 6), but not much different from the results obtained in Comparative Example 2. No improvement was observed in the loosening and texture of cooked rice.

Next, two types of amylases having different optimum temperatures were used in combination, and the effects of the combination of amylases on the unraveling of rice and the improvement of texture were examined.
As shown in Table 2, when the combination of amylases used in Examples 1 and 2, that is, a combination of heat-resistant α-amylase and α-amylase, was used in the rice cooking process, a single type of amylase was used (comparison) Compared with Examples 2-6), the binding rate was further reduced, and it was confirmed that the loosening of cooked rice was remarkably improved. Moreover, also about the food texture, it was confirmed that the restorability is further improved and the food texture is extremely excellent with appropriate stickiness and hardness. In addition, when one type of thermostable α-amylase is used and the amount used is increased (Comparative Example 6), it is better to use a combination of thermostable α-amylase and α-amylase. Regarding the texture, it was also confirmed that the improvement effect was very high.
From this, it can be said that the method for producing processed cooked rice used in the rice cooking process by combining heat-resistant α-amylase and α-amylase is an extremely useful method for remarkably improving both the loosening and texture of cooked rice.
In addition, when heat-resistant α-amylase and glucoamylase are combined and used in the rice cooking process (Example 3), when one type of heat-resistant α-amylase is used and the amount used is increased (Comparative Example 6). ), The texture improvement effect was seen.
From this, the method for producing processed cooked rice that uses two types of amylases with different optimal working temperatures in the rice cooking process is more relaxed than when no enzyme is used or when one type of amylase is used. It can be said that the texture can be improved. In addition, such a method for producing processed cooked rice can be said to improve the processability in cooked rice processing and improve yield because the loosening of cooked rice has been improved.

  Next, the effect of the present invention was confirmed by the following test when the rice cooking yield was reduced in the rice cooking process during the production of the expanded dry rice.

Example 4
In Example 2, it manufactured similarly except having changed the amount of water at the time of rice cooking to 140% with respect to the weight of rice, and obtained puffed dry rice. The rice cooking yield after cooking at this time was 2.17 (corresponding to 60% of moisture after cooking).

(Comparative Example 7)
Production was carried out in the same manner as in Example 4 except that no enzyme was used, and swollen and dried rice was obtained.

  About the cooked rice after the primary drying in Example 4 and Comparative Example 7, the binding rate was calculated by the same method as described above, and the loosening of the cooked rice was evaluated. Evaluation was made into 5 step | paragraph evaluation and performed the comparative example 7 as "2" which hits the 2nd from the bottom.

  The expanded and dried rice obtained in Example 4 and Comparative Example 7 is put into a cup-shaped plastic container, 7.2 g of powdered soup, 3 g of dried egg, 2.5 g of freeze-dried pork, 1.3 g of freeze-dried shrimp, dried green onion 0 .9 g was added, mixed, 160 ml of water at 25 ° C. was added, lightly capped, cooked in a microwave oven at 500 W for 5 minutes and 30 seconds, steamed for 1 minute, then taken out of the microwave oven and stirred well to make an instant fried rice. This was eaten by five skilled panelists, and the texture of the cooked rice after restoration was evaluated. Evaluation was made into 5 step | paragraph evaluation and performed the comparative example 7 as "2" which hits the 2nd from the bottom.

  Table 3 shows the binding rates of Example 4 and Comparative Example 7, the looseness of cooked rice, and the results of sensory evaluation.

As shown in Table 3, when the rice cooking yield in the rice cooking process is reduced, the binding rate is low without using an enzyme, but by using two types of amylases with different optimum working temperatures in the rice cooking process. Further, it was confirmed that the binding rate was further lowered and the loosening of cooked rice was further improved. Moreover, about the food texture, it was confirmed that the restorability is improved and the food texture is excellent.
From this, even if the rice cooking yield in the rice cooking process changes, the method for producing processed rice that is used in the rice cooking process by combining two types of amylases having different optimum temperatures is compared to the case where no enzyme is used. It can be said that the loosening and texture can be improved.

(Example 5)
Rice was cooked in the same manner as in Example 2 to obtain cooked rice having a rice cooking yield of 2.37 (equivalent to 63% moisture after cooking).
To 100 parts by weight of the cooked rice, 5 parts by weight of vegetables and 7 parts by weight of fried eggs, 5 parts by weight of seasoning, and 1.5 parts by weight of vegetable oil are added and stirred and mixed. The fried rice was fried at 0 ° C. and frozen by a conventional method to obtain a frozen fried rice.
Also in this case, the loosening of the cooked rice was improved, the processing suitability in the frozen cooked rice processing was improved, and frozen rice with a stable quality with little freezing unevenness was obtained.
When 250g of this frozen fried rice was cooked for 4.5 minutes at 500W using a microwave oven, the fried rice after cooking is cooked with cooked rice, and the cooked rice is well-frozen at the time of manufacture. And the texture was very good.
Thus, it can be said that the method for producing processed cooked rice using a combination of two types of amylases having different optimum working temperatures is also useful for producing frozen cooked rice.

  In addition, in the said Example, although illustrated about the manufacturing method of the processed cooked rice including the rice cooking process which uses two types of amylases from which an action optimal temperature differs, when using in combination of 3 or more types of amylases from which an action optimal temperature differs (Enzyme addition amount: Enzyme 1 90 U / kettle, Enzyme 2 45 U / kettle, Enzyme 3 45 U / kettle) were tested in the same manner as in the Examples to confirm the effect of the present invention. Even in this case, it was confirmed that the cooked rice can be produced with good quality, with little variation in texture during eating, and excellent quality.

Thus, the manufacturing method of the processed cooked rice in this invention includes the rice cooking process which uses two or more types of amylases from which an optimal temperature of action differs, and in the rice cooking process like the Example mentioned above, it is excellent in loosening. The cooked rice is obtained and processed in various ways to produce processed rice with excellent quality.
Therefore, for the processing of cooked rice after the rice cooking process, the conventional process of manufacturing cooked rice can be applied as it is, not only the expanded and frozen rice illustrated in the examples, but also α-ized rice, vacuum freeze-dried rice It can be widely applied to other processed rice such as chilled rice.

  The method for producing processed cooked rice of the present invention is useful in the production of cooked cooked rice that is excellent in the looseness and texture of cooked rice.

Claims (3)

  A method for producing processed cooked rice comprising a rice cooking step in which a non-heat-resistant α-amylase and a heat-resistant α-amylase having different optimum temperatures are used.   The method for producing processed cooked rice according to claim 1, wherein the optimum temperature of action of the non-thermostable α-amylase is 30 to 60 ° C, and the optimum temperature of action of the heat resistant α-amylase is 60 to 100 ° C. The method for producing processed cooked rice according to claim 1 or 2, wherein the processed cooked rice is pregelatinized rice, expanded dried rice, vacuum freeze-dried rice, chilled cooked rice, or frozen cooked rice.